The objective of the proposed research is to identify the most sensitive, specific, and reproducible screening methods for detecting disturbed central and peripheral nervous system function in workers exposed to lead. Earlier studies of lead neuropathy have suffered from methodological inconsistencies and inconclusive results. The proposed study will be a prospective evaluation of cohorts of 40 lead-exposed workers and 40 unexposed controls in which subjects will be tested three times over a three-year period. A 30% sample of subjects will be retested immediately after each of the three testing sessions to assess reproducibility of nerve conduction testing. The following data will be collected from each participant in the study: 1) work and medical history and demographic information; 2) motor and sensory nerve conduction evaluation of ulnar, peroneal, and sural nerves; 3) clinical neurologic examination; 4) psychologic measures of memory, intelligence, and dexterity; 5) blood lead and zinc protoporphyrin levels (collected bi-monthly). Upon completion of the study, we will be able to recommend a standard methodology for evaluating neurologic effects of lead, and of other neurotoxins in occupational settings. Not only would such a protocol improve the comparability of studies performed by different investigators, but its systematized implementation by trained technicians would facilitate subsequent studies. Furthermore, more precise dose-response relationships between neurotoxin exposure levels and neurologic effects could be developed and then used to establish permissable exposure levels in the workplace. Since many new chemicals will be introduced into industry in the future, the availability of this method and its criteria would greatly facilitate the evaluation of exposed workers.